CK5 - The Full-Size GM Off Road Community

It's been a while since I posted any updates to the program, so I thought I'd at least put a link here for one of the "newer" ones.....

There's more to come but this one has a cleaner interface and should be a little easier to understand and use.

:usaflag: Enjoy! :usaflag:


Click Here: It's on my Uber Fancy Website..... (http://www.gregblanchette.com/)




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Damn, it doesn't work with MS Works... /forums/images/graemlins/doah.gif

[ QUOTE ]
Damn, it doesn't work with MS Works... /forums/images/graemlins/doah.gif

[/ QUOTE ]

Once you find a machine to open it with....you'll understand why! /forums/images/graemlins/cool.gif

That is just downright sweet! Now if I could figure it out /forums/images/graemlins/histerical.gif
I get the idea, but most of its greek to me /forums/images/graemlins/whistling.gif

WOW, nice upgrade!

Thanks. /forums/images/graemlins/waytogo.gif /forums/images/graemlins/peace.gif

Very nice. How do you apply it to figure out the front links?
Thanx for the file.

[ QUOTE ]
Very nice. How do you apply it to figure out the front links?
Thanx for the file.

[/ QUOTE ]


Just flip your monitor around.... /forums/images/graemlins/histerical.gif

Seriously, I think it's the same calcs....just substitute the word "AntiDive" for "AntiSquat" whereever you see it. The prepopulated data in that sheet is actually a design for my FRONT suspension, and it seems to work fine.

Greg, I thought there was something in there that calculated the safety factor on links and all that and I'm not seeing it? I see the forces applied to the links and all but nothing about tube diameter and wall thickness and such. FYI, I ran all my specs of my truck and came up with exactly what I had figured out on my own the hard way /forums/images/graemlins/cool.gif

This is seriously nice work man! /forums/images/graemlins/eek.gif

Thank you for making this available. /forums/images/graemlins/thumb.gif

Finally got Excel for my Mac so I could open this thing. Very nice work Greg... /forums/images/graemlins/thumb.gif /forums/images/graemlins/thumb.gif /forums/images/graemlins/thumb.gif

BIGJ

Looks good

/forums/images/graemlins/peace.gif

Now I may actually educate myself on this four link stuff so I can actually answer a question or two when I get PM'ed with them...................

Or just go into the drug test kit selling business..............


Looks good, thanks /forums/images/graemlins/peace.gif /forums/images/graemlins/peace.gif /forums/images/graemlins/peace.gif

Jason,

It's a multi-tab worksheet....click on the tabs at the bottom to flip to the other info you seek. /forums/images/graemlins/cool.gif

Greg,
DO you make the program yourself? I played with it a little last night. Very nicely done. Isnt there a way in excell to see the equations? Thanks for the great stuff.

To switch from numbers to equations you hit Ctrl + `
(note - left side of keyboard above tab)

[ QUOTE ]
Greg,
DO you make the program yourself?

[/ QUOTE ]

He had some help /forums/images/graemlins/whistling.gif

[ QUOTE ]
Isnt there a way in excell to see the equations? Thanks for the great stuff.

[/ QUOTE ]

Do you really want to see all the calculations? /forums/images/graemlins/ignore.gif

Allot of head scratching went into those! /forums/images/graemlins/thinking.gif

[ QUOTE ]
Greg,
DO you make the program yourself? I played with it a little last night. Very nicely done. Isnt there a way in excell to see the equations? Thanks for the great stuff.

[/ QUOTE ]



From Cell W3:

"Created 2003.12.01 by Dan Barcroft & Greg Blanchette"



Most good ideas require more than one brain!!! /forums/images/graemlins/peace.gif

Right Click...
Save Target As...
ExcelCAD v2.1.xls...
Click Save...
Done! /forums/images/graemlins/waytogo.gif /forums/images/graemlins/pimp.gif

Thanks for all your hard work Dan & Greg; this will be a big help towards the end of the summer when I finally install my rear triangulated 4 link. /forums/images/graemlins/pimp.gif /forums/images/graemlins/woot.gif

Greg-

I work in a marketing research company that has a dedicated team of people who work MS Office products like no one I've ever seen... until now. I have to say this is one very impressive piece of work. Thanks very much for creating this excellent tool for everyone who has little to no clue about the math behind this spreadsheet. /forums/images/graemlins/bow.gif

-Dan

One question for you... when using the materials selection tool, I'm looking to better understand the F.S. #'s that change when changing (for example) the outside diameter from 2" down to 1.75". I can see the lb ratings change in the I column, but I don't really grasp what the changes in the Factorys of Safty are about. Seems like the higher the number the better... Any help for the meager?

Thanks,
-Dan

[ QUOTE ]
One question for you... when using the materials selection tool, I'm looking to better understand the F.S. #'s that change when changing (for example) the outside diameter from 2" down to 1.75". I can see the lb ratings change in the I column, but I don't really grasp what the changes in the Factorys of Safty are about. Seems like the higher the number the better... Any help for the meager?

Thanks,
-Dan

[/ QUOTE ]





The FS values are "dimensionless"....they have no units, so they are only useful in comparing to other FS values. In some ways it's better because it "normalizes" everything down to a value that can be compared.

I remember Triaged gave some general guidlines for what the values should be for a front suspension design vs. rear (hint: a steering suspension should have a higher safety factor since it can KILL you!)

If you play with the numbers for a while you will see that getting certain FS values higher is pretty hard to do. For example, a Bending FS is mostly a function of the length of the tube you use. You can change the thickness or OD of the tube and get minor improvements, but to really make the FS climb, you need to shorten the link. Stuff like that can be really insightful when you come up with a design you like..... it really is all about compromises in link design, and the more you understand it, the better able you are to choose your compromises wisely!!! /forums/images/graemlins/thumb.gif

Thanks for the clarification. My primary objective right now is more to learn and understand what AS(anti-squat), IC(instant-center) and RC(roll-center/axis) really mean when designing a chassis or link system. Your tool will CERTAINLY help in my learning process.

My next major question is around calculating COG values for different vehicles. I've found a few sites that have calculators online, but I'm at a loss for what some of the values required are describing. FOR EXAMPLE (http://www.longacreracing.com/articles/art.asp?ARTID=22)

Thanks again Greg! /forums/images/graemlins/bow.gif

-Dan

The reason for not putting cog calculation into the ExcelCAD was becasue there are already some good ones on the net. This is one of the best I have seen.

http://www.jeepaholics.com/tech/cog/

Wow! More excellent content to *attempt* to absorb! Thanks for the good link! /forums/images/graemlins/peace.gif

-Dan

[ QUOTE ]
RC(roll-center/axis)

[/ QUOTE ]

Note that those are NOT the same thing. RC is the point in space where the rear can be said to pivot around when also considering the front's RC. The line btwn the two RC's is the vehicle's Roll Axis.
RA is the roll axis of either particular suspension system. In the rear it's angle relative to horizontal determines the amount of rear steer, and in which direction, when twisted up.
To be engineer correct we should probably state:
RC(f) = Roll Center, front
RC(r) = Roll Center, rear
RA(v) = Roll Axis, vehicle
RA(f) = Roll Axis, front
RA(r) = Roll Axis, rear
But that's too danged complicated.


Yes. Look who turned orange. It's that gainfully employed thing......

my brain is melting It hurts It hurts
This is great info guys /forums/images/graemlins/thumb.gif

I think Greg is still out of town...

Someone that knows Excel/VisualBasic want to help me do some final messing with V2.1 (or maybe it should be V3.0 because it is so much better!). I'm currious if the macros will work on someone elses computer.

I've been trying to overcome my long term funk and get this show on the road again. As such, I've been evaluating link designs again.

First off, thank you VERY VERY much Greg and Dan for the fine work. It amazes me every time I look at it.

Second, this deserves to stay somewhere near the top in CoG, so time to top it up again.

Finally, seems there are a few minor bugs, or I misunderstand something. I think you should flip the sign for cells G19, G20, and G22. I also notice references to "Solver" and "Axis ActiveX control module" which appears to be a Nero Wave editor addin. These pop up as "missing reference" errors when you edit formula cells.

Man, with the link lengths I need, that bending FS is an SOB! I'm having trouble getting it above *1* in my current designs!

Baddog, Did you try pipe? LOL

How much work would it be to add a driveshaft plunge calc? That is one thing I tend to be concerned about.

Darn, there is no material selection for pipe! :mad:

:haha:

Just heard from Dan, he's made some corrections/updates. Newest can be found here.

Bar Link Calc V3.0 (http://home.earthlink.net/~triaged/Files/4BarLinkV3.0.zip)

Dan, let me if new versions come out.

If there is an easily found place to add in an 'I' value you can start looking at built-up sections. The bending loads aren't the only reason that dez trucks use a built-up lower rather than a single tube.

Thanks, already crossed my mind, but I have no idea how to calculate based on that. But as long as the base factor is close to 1, most anything of consequence should raise it dramatically. My several thoughts include a piece of 1/4" angle or even appropriate sized channel scabbed on the bottom, or maybe even a buttress tube to add vertical dimension like the WMS guys do. Channel would give vertical walls which would be good. Angle would give a narrow edge which might or might not be good depending. Biggest problem with that though is that you now have a "bottom" on the link, and fine adjustment is no longer possible. It's full turn or nothing, much like my drag link with the ram tab welded on. Of course, rear suspension shouldn't be all that sensitive to fine adjustment like that, being that it's mostly pinion angle that would be affected. Front might be more sensitive with castor issues to consider.

Wouldn't it only be a half turn b/c you can move the joint(s) in 180* increments?

I would avoid any of the Structural shapes (Channel, Angle, I-beams, W-beams, etc.) b/c of their hot rolled condition and their load direction specific design.
Have a look at Newhan's Truck (http://www.race-dezert.com/forum/showthread.php?t=7420)for one example of a built-up lower link. Specifically this pic. (http://race-dezert.com/skunkz/newhan/27.jpg)

Well, I was really talking about the normal "twist the link" adjustment, but yeah, you could drop and end, turn it, and replace for 25% turn adjustment.

Nice link, but wow, lots of work. I was really thinking of DOM tube with a piece of channel scabbed on the bottom just to get the vertical load help.

I figure there's 30-40 hrs in each arm. Didn't figure you'd want to go to that much work, just used it as an example of thinking 'outside the straight round tube'.
The strength of an I or W beam is in the flanges and the distance btwn them, not in the web. How about two 1.5"x .120 tubes stacked about 2" apart? Put some spreaders or a solid web in btwn them. That would skyrocket the 'I' in the direction you need.

Plug in some ridiculous round tube size and see what it does for you. Try something like 3.0" x .075 wall. Obviously you wouldn't want to use .075 where it will hit rocks, but see what it does for the FS as an experiment. BTW, 3.0 x .075 roughly weighs the same per foot as 2.0 x .120
Geometry is always your friend......

The stacked tubes has crossed my mind. Sort of like the WMS boys run. But that still leaves round tube on the bottom which can be dented, reducing it's strength dramatically, though it wouldn't change the strength of the constructed length nearly as much as it would a single link. Biggest problem I see with the tall links is clearance. I'm already having trouble working out what to do with stuff in that area (like exhaust).



Still seems to me that the channel should provide the required strength, but maybe I'm missing something. With it scabbed on the bottom of the link, the flanges would be vertical, and welded to the link, so they could not deflect, and that provides the strength oriented in the desired direction (up/down). The web would be horizontal forming a sort of skid plate to protect the round tube link which continues to handle the comp/tensile forces. Simple, fast, cheap, and compact. Not nearly as good as the links you suggest, but should be more than good enough based on information from people who run regular straight links (i.e. they hold up pretty well till you fall on them hard).

Just been my observation that the strength of stuff like Channel etc. hasn't been worth the weight.

Crap...

I just noticed I forgot something in the Anti-Squat CG calculation. Of course I would get the sprung mass CG right (which isn't used for any calculations :doah: )

I blame this all on Greg for moving to the other side of the Courtry and not being able to help me and check everything :grin: :1zhelp:

I fixed it and used the names (insted of cell references) to do the calculation. You might notice that I forgot to add in the CG of the unsprung mass (oops).

I fixed it now and the fixed one is at the same link
http://home.earthlink.net/~triaged/Files/4BarLinkV3.0.zip

It only makes sence that the AS CG would be between the sprung mass CG and the overall CG. I don't know what I was thinking letting it get out with that big (8% in my example) of an error.

You guys will also notice my start of a driveshaft section under the travel tab. It isn't working yet so just ignore it (unless you want to make it work and email it to me :D ).

Thanks for the driveshaft part. I'll look at it when I've some time. May or may not be able to make it work (likely the latter :o ).